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Call for ContributionsHETEROCYCLES Special Issue Vol. 99 in honor of Professor Tohru Fukuyama on 70th Birthday

Submission deadline: September 10, 2018
On the occasion of Professor Tohru Fukuyama's 70th birthday, HETEROCYCLES editorial office is planning to publish special anniversary issue on April 1, 2019 as Vol. 99. Authors are invited to submit their work to this topical issue.
Authors wishing to submit their manuscript should contact editorial office via e-mail by the end of May, 2018. Manuscript should reach the editorial office no later than September 10, 2018.
Contact: submit@heterocycles.com

March 5, 2018

Heterocycles Award
HETEROCYCLES is pleased to announce Heterocycles Award.
In recognition of an outstanding oral presentation at the 47th Congress of Heterocyclic ChemistrySee more

December 13, 2017

Call for ContributionsHETEROCYCLES Special Issue Vol. 97 in honor of Professor Kiyoshi Tomioka on 70th Birthday

Submission deadline: February 15, 2018
On the occasion of Professor Kiyoshi Tomioka's 70th birthday, HETEROCYCLES editorial office is planning to publish special anniversary issue on September 1, 2018 as Vol. 97. Authors are invited to submit their work to this topical issue.
Authors wishing to submit their manuscript should contact editorial office via e-mail by the end of November, 2017. Manuscript should reach the editorial office no later than February 15, 2018.
Contact: submit@heterocycles.com

Abstract

The synthesis of several representatives of the previously unknown N-alkyl-nortropane-6-spirohydantoin ring system by Bucherer-Bergs reaction of 8-alkyl-8-azabicyclo[3.2.1]octan-6-ones is described. 3-Oxo derivatives of the parent structure were also prepared. The stereochemical outcome of the Bucherer-Bergs reaction is discussed on the basis of 1H-nmr and 13C-nmr data.

■ A Synthesis of 1,2,3,4-Tetrahydro-1,6-naphthyridines

Abstract

8-Cyano-3,4-dihydro-1,6-naphthyridin-2(1H)-ones were obtained by nucleophilic substitution of the methoxyl group of 5-cyano-3,4-dihydro-6-methoxy-2(1H)-pyridones (5a-d) by malononitrile or cyanoacetamide followed by cyclization in acidic or basic medium.

Abstract

Indole, 2-methylindole, 2-phenylindole, and primary aromatic amines react with iodosobenzene diacetate leading both to 2-arylamino-3-arylimino-3H-indole in the case of indole and 2-methylindole, and to 2-phenyl-3-arylimino-3H-indole in the case of 2-phenylindole. The reaction is believed to proceed through the formation of a nitrenium ion formed by the interaction of iodosobenzene diacetate and primary aromatic amines and the mechanism is supported by experimental evidences. The methyl elimination from 2-methylindole is explained on the basis of the isolation of the possible intermediate and the formation of an aminal, whose decomposition leads to the reaction products. The intermediate aminal is proposed on the basis of the bis-(2-methylindol-3-yl)methane formation.

Abstract

Levoglucosenone (1,6-anhydro-3,4-dideoxy-β-D-glycero-hex-3-enopyranos-2-ulose, 1) was converted to give 1,6:3,4-dianhydro-β-D-talopyranose (8) in good yield through stereoselective trans-iodoacetoxylation followed by basic hydrolysis.

■ NOE Difference Spectroscopy Applied in Stereochemical Investigations of Two Diastereomeric Indoloquinolizidine Alcohols, Significant in the Preparation of Geissoschizine-Type Compounds

Reija Jokela

*Laboratory for Organic and Bioorganic Chemistry, Technical University of Helsinki, SF-02150 Espoo, Finland

Abstract

Complete 1H-nmr data were recorded for indoloquinolizidine alcohols (2a) and (2b), significant intermediates in the preparation of geissoschizine-type compounds, and for their benzoyl derivatives (3a) and (3b). The stereochemistry was deduced from NOE measurements.

■ The Structures of Two Isomeric N-Formates from 3-O-Acetylsolasodine

Abstract

The structures of two isomeric N-formates, I (1) and II (2), prepared from O-acetylsolasodine, were determined by X-ray crystalographic analyses, and the isomerism between them was shown to be caused by the epimerization at C-22 during the formylation.

Abstract

2-(Pyrid-2’-yl)amino-3-chloro-5,6-dicyanopyrazines (IIa, IId, and IIe) and 2-(pyrid-2’-yl)amino-3-chloro-6-nitroquinoxalines (Va-c) were isolated for the first time in the course of the reaction of 2,3-dichloro-5,6-dicyanopyrazine (I) and 2,3-dichloro-6-nitroquinoxaline (IVa), respectively, with 2-aminopyridines. Furthermore, the yield of pyrido[1’,2’:1,2]imidazo[4,5-b]quinoxalines was remarkably improved due to the modification of the reaction conditions.

■ Alkaloid N-Oxides

Abstract

More than 200 aliphatic and aromatic N-oxides have been individuated among natural-occurring alkaloids. The structures of these compounds as well as the role that N-oxides have in the synthesis and the chemical modification of alkaloids are reviewed.

■ Synthesis of Mixed Thiophene-Pyrrole Heterocycles

Abstract

The synthesis of mixed thiophene-pyrrole heterocycles has been reviewed. The systems under consideration are various isomeric thienylpyrroles as well as tricyclic analogs containing non-condensed combinations of two or three pyrrole and thiophene units.